Get your boxes of tissues and then you can read Yumi and Monster by Kam Redlawsk. Due in September 2025 I read this via an online reader copy. And while I am curious how the finished copy will look, I am not sure I can read this bittersweet picture book.
Yumi is a little girl who loves to play, but both her parents and the doctors say that will change. One day she is given a cane to help her walk (only we don’t hear the action around this, just see a red can against the black and white illustrations). We also see a large Monster in the trees near Yumi’s home. Sometimes the monster is at the window, asking her to come out, sometimes it clicks its antlers on the window. But all the while Yumi is growing more tired and more sick. One day, Yumi follows the monster into the woods, in hopes of losing the monster and things can go back to normal. Only to find herself lost and eventually alone. But also, learning that the Monster is part of her and she is part of him.
The author afterward has the real story behind Yumi’s journey. It is based on Redlawsk’s own rare illness. As Yumi will eventually be shown, Redlawsk is in a wheelchair, but she wants to share the story of how we all have a shadow in our lives occasionally and how we need the strength to get through it. I love how Yumi gets her name (because it sounded like You and Me to the author) and the illustrations are a powerful piece of the larger picture. 
Color usage becomes the most important part of the artwork. Red is used to highlight the important parts of things. The sepia and grays then form a background to let that color pop off the page. The story is emotional to say the least, but that emotion partly comes from the sweet, cute and telling images. Two styles of art (a more chibi like look and a manga, superhero comic look) are used and this difference only adds to things. It is a delightful read that will hit each reader differently. It is adaptable for all ages, but know your reader as it has a unique formula.